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ID:43515649
大小:1.05 MB
页数:89页
时间:2019-10-09
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1、ProcessDescriptionandControlZhaoFangOperatingSystems-forthecollagestudentsGoalsforTodayWhatisaProcess?ProcessStatesProcessDatastructuresProcessControlExecutionoftheOperatingSystemUNIXSVR4ProcessManagementRequirementsofanOSInterleavetheexecutionofsevera
2、lprocessestomaximizeprocessorutilizationwhileprovidingreasonableresponsetimeAllocateresourcestoprocessesSupportinterprocesscommunicationandusercreationofprocesses3ManageExecutionofApplicationsResourcesmadeavailabletomultipleapplicationsProcessorisswitched
3、amongmultipleapplicationTheprocessorandI/Odevicescanbeusedefficiently4ProcessAprograminexecutionAninstanceofaprogramrunningonacomputerTheentitythatcanbeassignedtoandexecutedonaprocessorAunitofactivitycharacterizedbytheexecutionofasequenceofinstructions,a
4、currentstate,andanassociatedsetofsysteminstructions5ProcessCompositionAprocessiscomprisedof:Programcode(possiblyshared)AsetofdataAnumberofattributesdescribingthestateoftheprocessProcessElementsIdentifierStatePriorityProgramcounterMemorypointersConte
5、xtdataI/OstatusinformationAccountinginformation7ProcessControlBlockContainstheprocesselementsCreatedandmanagebytheoperatingsystemAllowssupportformultipleprocesses8TraceoftheProcessThebehaviorofanindividualprocessisshownbylistingthesequenceofinstructions
6、thatareexecutedThislistiscalledaTraceDispatcherisasmallprogramwhichswitchestheprocessorfromoneprocesstoanotherProcessExecutionConsiderthreeprocessesbeingexecutedAllareinmemory(plusthedispatcher)Letsignorevirtualmemoryforthis.TracefromtheprocessespointsE
7、achprocessrunstocompletionTracefromProcessorspointsTimeoutI/OTracefromProcessorspointswecandrawatimelineofCPUactivity,identifyingthestatesoftheprocessesandDispatcherExampleExecution14Two-StateProcessModelProcessmaybeinoneoftwostatesRunningNot-runningQueui
8、ngDiagramEtc…processesmovedbythedispatcheroftheOStotheCPUthenbacktothequeueuntilthetaskiscompetedProcessBirthandDeathCreationTerminationNewbatchjobNormalCompletionInteractiveLoginMemoryun
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